The architecture deployed in a cloud computing data center, with fat-tree networking design, supports 100GbE, 200GbE server access and 400GbE Spine-Leaf configurations.
Cisco QDD-400G-FR4-S Compatible 400G QSFP-DD FR4 PAM4 CWDM Optical Transceiver Module (CWDM SMF LC 2km DDM with FEC)
Cisco QDD-400G-FR4-S Compatible 400GBASE-FR4 is a 400Gb/s Quad Small Form Factor Pluggable Dual Density (QSFP-DD) optical transceiver that supports link lengths up to 2km via duplex LC connectors. It converts eight 50Gb/s (PAM4) electrical inputs into four CWDM optical signals and multiplexes them into a single 400Gb/s optical transmission. Conversely, on the receiver side, the module multiplexes the 400Gb/s optical input photodemultiplexing into 4-channel CWDM optical signals and converts them into 8-channel 50Gb/s (PAM4) electrical output data. The four CWDM channels have center wavelengths of 1271, 1291, 1311, and 1331 nm and are primarily used for interconnecting data centers, 400G Ethernet.